Abstract
Herein, we investigate the impacts of sunlight on different optical parameters of borosilicate glasses containing nickel, barium, and cadmium oxides. We studied the influence of sunlight on the optical band gap (Eg), Urbach energy (EU), refractive index (n), and nonlinear refractive index (n2) at different times of irradiations; t = 0, 40, 60, and 120 minutes. The absorbance of all glass samples showed a decreasing behavior, particularly in the ultraviolet (UV) range. The reduction in the UV absorption band at around 307 nm is ascribed to the photo-reduction of Fe3+ to Fe2+, producing a decrease in the amount of Fe3+ in the glass samples. The percent of changes for the studied optical parameters such as Eg, EU, n, and n2 is insignificant (<10%), confirming the glasses' stability under the effect of solar irradiation. The good stability of the investigated glasses makes them good candidates for optical applications, especially those exposed repeatedly to sunlight, such as smart windows and solar cell panels.